<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        function Person(name,age){
            this.name = name 
            this.age = age
        }
        Person.prototype.eat = function(){
            console.log('吃东西');
        }
        function Student(sex,name,age){
            Person.call(this,name,age);
            this.sex = sex
        }
        Student.prototype = new Person()
        let stu = new Student('男','feng',24)
        console.dir(stu);
        console.dir(stu.eat())
    </script>
</body>
</html>